Washington (CNN) -- A congressional investigation into the Defense Department's response to the deadly attacks in Benghazi, Libya, found that the Obama administration failed to protect the compound and recognize the severity of the deteriorating security situation.
For the partisan report, the investigative arm of the Republican-led House Armed Services Committee pored over thousands of pages of classified and unclassified written material, witness testimony and classified briefings to piece together the events of September 11, 2012, that killed four Americans, including Ambassador Christopher Stevens.
"This report should be considered one component of continuing comprehensive Benghazi related oversight underway in the U.S. House of Representatives," the report says.
Since the attack a year and a half ago, conservatives have been skeptical about the Obama administration's account of the events and say they suspect a cover-up. Just after the attack on the U.S. compound, Obama administration officials said the violence was a result of a protest over a controversial film about Islam made by an American -- a claim that has proved to be untrue.
While this investigation focused on the role of the Defense Department, it blames the Obama administration and Secretary of State Hillary Clinton's State Department for failing to protect the compound that housed U.S. personnel.
The report found:
• White House officials failed to comprehend or ignored the dramatically deteriorating security situation in Libya and the growing threat to U.S. interests in the region.
• U.S. personnel in Benghazi were woefully vulnerable in September 2012 because there was no intelligence of a specific "imminent" threat in Libya, and the State Department, which has primary responsibility for diplomatic security, favored a reduction of Department of Defense security personnel in Libya before the attack.
• Defense Department officials believed nearly from the outset of violence in Benghazi that it was a terrorist attack rather than a protest gone awry.
• The U.S. military's response to the Benghazi attack was severely degraded because of the location and readiness posture of U.S. forces, and because of a lack of clarity about how the terrorist action was unfolding.
• Given the uncertainty about the prospective length and scope of the attack, military commanders did not take all possible steps to prepare for a more extended operation.
• There was no "stand down" order issued to U.S. military personnel in Tripoli who sought to join the fight in Benghazi. However, there was confusion about the roles and responsibilities of the personnel.
• The Department of Defense is working to correct many weaknesses revealed by the Benghazi attack, but the global security situation is still deteriorating and military resources continue to decline.